Extract the Nibble from an 8-bit Register

Code

#include <stdio.h>

unsigned char extractNibble(unsigned char reg, int pos) {
    // Write your code here
    if( (reg > 255) || (reg < 0) )
        return -1;
    if ((bool)pos)
        return ((reg & 0xf0) >> 4);
    else
        return (reg & 0x0f);
}

int main() {
    unsigned char reg;
    int pos;
    scanf("%hhu %d", &reg, &pos);
    printf("%d", extractNibble(reg, pos));
    return 0;
}

Solving Approach

Since it is only a 8bit char, and the pos value can be 0 or 1, I would rather use them as boolean and return appropriate nibble use masking and bit-shifting.